Fix building with -C

Makefile

@@ -91,10 +91,10 @@ clean:
 	@rm -rf $(OUTPUTDIR)
 
 $(MODULEDIRS):
-	$(MAKE) -C $@ $(MAKECMDGOALS)$(MAKEFLAGS)
+	$(MAKE) -C $@ $(MAKECMDGOALS) -$(MAKEFLAGS)
 
 $(NYXDIR):
-	$(MAKE) -C $@ $(MAKECMDGOALS)$(MAKEFLAGS)
+	$(MAKE) -C $@ $(MAKECMDGOALS) -$(MAKEFLAGS)
 
 $(TARGET).bin: $(BUILDDIR)/$(TARGET)/$(TARGET).elf $(MODULEDIRS) $(NYXDIR)
 	$(OBJCOPY) -S -O binary $< $(OUTPUTDIR)/$@